Apparatus for burning fuel



Aug. 3, 1943. R. E. BRESSLER APPARATUS FOR BURNING FUEL Filed June 21,1941 I'm/e berf Z firessjer u nin c e mummy Also, it is an objector theinyention apparatus 1 I "Referring nowin detailftothat embodimentpf;

1:1 ounge;

I outinthefapbended oleims The apparatus; with which the, present invenis (C Hoe-101 successively, oceurringl burnihgfiveyjcl'esi In one 1 saidcycie, the} fuel isibiirnei faster man it is;

t One ofjthelobjectsfot the; present invention is to royide im ro eo meas ttor eontrollirj gthe cyclingpctionot the apparatus andwhichnieahs isSimple in eonstr ietion Ior 1ow cost prodnetion v and at the same time:is automatic} ac urate and dependable so at i to he trouble tree in'operdtion overlong periodsfofusfli reaaw: the fuel bed and wiie 'tn.fuel bed has burned downto a preueter men depth nothr Seriail N6.399,111

biowe tothwumer to support oombiistion the biowe'rgg 1:

j. Another obje t. oi the invention is to provide improved eans forloontrolling thebyoling ae-u tion of the apparatus, which innotion slbyreason o! the ohangefinpressure ot th'e supplied. air,

1 thus eiiminatingjthe necessity for the used! in; t

dependent cyole timing elements,jwhichiiierease means for this purpose,whereby the oyeling action: is ohtained ,without, momentarily; stoppingthe entire apparatus, thus relieving "the driving:

' motor of the epparatus i'r'oin ,imd iej startingtorquesjandimaterially reducing the eonsumpption 0! powerrequireo fortheaDDaratusQand The above mentioned objeetsoi the invention,

nithed 'aw n i Fig fl is a iew injside el evati'o nota fuel burn ingapparatus andl assoeiated l ecltrie circuit em;

bodying the invention," with parts of l the appee ratueshownin sectionor fasbrok'en away, better tov illustrate the parts involved. I

'Fig; 2 is a fverticaljsectional' .view, on an (e nf 'sive elements ordiaphragn s embodied in" the the invehtion illustrated ingthel drawinand heiicalfiight Ntheteon of a1 dialmeter epm oxi-i v V matingthe'insidegiiar eterv of eaidtubgjSectiong;

thereiorefasshring moreTeconoinical operatiomj 1 i hopperfi andthrough,the t rounded bottom or. the retort endmhere 1tter- 40 m n n the adrn aee; o gi g retortjare tuyeres I Q whereby gir under pressure e 3 all inludes a feed ,tjube section s thaflextendsfhrE-l V tweejrijthefrea'rend'oY; thelower portion of" the hopper 6 and 'the fuel inlet openingI5] I ,The

15181 feedingmea n's ras herein. showri also in'cludesb a secondtublesection l1 inaxigl alignment' with] thef rt mentioned one and whichisdisposed.

*betweenhthe front end of th'e'lower portion of the hopbrangitherearside of an upright casing [8f located in' front of the hopper.

In the tube sections s and 'l1,,which are dis i 1 posedinthe'rhegliahiiiigfbf the hopper, is'looeted a feed 's crew-gthatincludes afshaft IQ WitI'iajf be sectionifijinto. the

' ing bearihg inthe fuel' in this part of theretortr 'I'hatendoi'jthefeed screwshaft disposed within thefllcasing IB- isoperativekjonnected by speed larged scale through one dune brefss ireresponegpjecislly to 1 thereoi, the iniproved appariat u s which is inthe John pr; an ,ungierfeed stoker; includes a bur ers; a. the! hopper 6and rediioi'ng gear ton. horizontal shaft; 22] thatis joujrnalled in theup perl e n d v or the casing "and extends trari$versely oiwthemsha ftof the feed' screw; one .nd; of 5 said. shaft 22 extends beyond one sideofgsaid easing where itisprovicieq with npfilleyj 23; T'hisrpulle y l sjdriven by abelt 24 fim"? m lwli-on n e d m t r -1 1' tshzaifttof'thelmotoj11); The other emiof S id; r tu e; shangext n swinojthe ca i g rime,

m we "8 51mm Qthei hfls'fl .f an or m of anytsuitab1ekindi(not-shownifseoured thereto i The duct {is operativelyconnected at one end damper for delivery to the fuel bed. i

to the disch arge or outlet side of the blower casing 8 and the otherend of said duct is connected to the inlet of the Windbox I. In the duct9 near the blower casin I'provide a damper 26 -mount'ed on a cross shaft2'! that is journalled in opposite sides of this part of the duct. Oneend of this shaft extends outside of the duct where it has fixedtheretoan arm 28. By means of the arm 28,;triedamper1may be rocked" from a ver-Q tical position, whereby' onl aininimum'voiume f air can pass thesame, to a horizontal position whereby a maximum volume of {air can passthe To move the damper from one position to the other, ,I provide anelectromagnetic: devicela having an armature 29a which ls -o'onnected alink 28a to the arm 28 on the; damper shaft.

When the device29 is deenorgized; the damper assumes a vertical andsubstantially clos ed-posi-' tion in the duct, and at this time only aminimum and opens at its otherend into the duct 9 at a point between thedamper 26 and the burner 5.

, tacts Wand 41 respectively that are carried on V tween its ends.

The high pressure diaphragm device 30 operates a single contact switch36 and the low pressure diaphragm device 3| operates adouble contactswitch 31. The'switch includes a fixed contact 36a and a contact 361)carried on one end of an arm 40 which is pivoted at its other end as atHi The diaphragm S4 of thedevijce 39 carries an axial stem' l l whichextends upwardly to en;

gage the under side of the arm 4i! at a point hesepaiatedfromitsassociated contact 36a.

Y Theiswitchfl includes space'd'ap'art fixed contoots- M and fi-respectively an associatedconone. end oii a. movable contact arm 48which is volume of air can passthe samewhen'the blower is being,driven;byflti'ie motora WI'ieiiQthe device zs'isenergized;the damper ismovedint its hoti z ohtal' andwide open position in the duct, per

mittiiigf thevpas'sage" of..' the maximlim Volume of airihroueh-theduot;If 3 I t From the alioyelit' .is ap'parent' that when the motor loiisenergized; the blower is driven to 7 provide air under-pressure and the.shaft" I ot the when t damper, 'lt isi'n'; its substantiall closedpos'ition'ai dthemoto lt' 'is energized the fuel is fdrt'o' the retortfaster than it can burn so that the, fuei bed ouilds u in depth andirovides, a

resist'eneehio the nassage of air' th'er'ethroug'h; which increases theressure-of said airvin' the duct; When thedamper Z6 is iiiitssubstantlaliy wide open oositionandthe motor "Li's energized; thefiiel'bed' burns atjarate fasterithanthe rate offeedofiiiei"thereto'sothatthe fuel bedburiis downindepth nddecr eases the, ressure or'theairinthe duct, The movemenvofthe' damper fromxits ciosedto itsopenpositionconstitutes one cycle of: burnihgeperation in a turninperiod of" the a paratus, after which the" damper-is caused to freturnto' its oiosed position to initiate a; succeeding cycle andtheoperationgoes on as before: j J

To move thefdaniper from one position to the other inorder to producethe cycling action, I

providethe'followlhgjmeans.

on an suitable part of'itfie apparatus'rprovide apairofipressi resensitive device's 3U'a'n'd.3Ire-' spectively. As best shown in Fig; 2;each device so -'31 includesapair of" opposed casing parts Ii -3srespectively, with the" peripheralmarginai I part ofa-nexibie diaphragm34* clamped bet'ween them; For convenience-infuture reference, I

I teimthedevicetlf the hlgh'pressure diaphragm device" and" the de'vicefiil the "low pressure" dia phragm device; The casing'partsioreachdevice 30%3'1 in connection'with the'diaph ragm slpro rides a pressureeiiamo'er-zt i'n'eacll device-at-the bottom" thereof. These deviceswan-d arm -be Y located at' any'conyenientplaceon the appara'tus andpreferably towardthefitontj'thereof: There:

tore, I have" shown both/of said devices as mounted on" a plate [to'tfiatis' arranged alcove the motor" m"-a issupportedty abracket itaz-Ktiihe' ttf opens at'one'end into the chamber 35, ofithe thigh:presure." diaphragm (lei/168130 and opens ati its, etherpe dfmto the" duct,9 ate point bet eon, the, casin is and the damperfztl filibtherflibjsfif hs' atoneend'into the chamber 35 of the fflow pressureddiaphragm device piyot'ally'mountedat its other end as at 49. Thediaphragm 34 of the device 3! carries an axial stem 50 'which .extendsupwardly to 'engage the' arm 48 atja'pointldetweenits endsf'A' spring 5|is so conn'ecte'd'to the aIInMl' as tonormally, hold i81'andassociatedarmature 59'. I 7 V 'I'Iiethermostat is usually: located in the room orspace being heated; andi thejliinit control, which" is associated withthe fuifnace; with which the apparatus. described is used, normallyfunctionsas aclosed switch." The transformer ineludes" primary and 81'respectively; I W

62 and 63" indicate the main current: onductors leading from a suitablesource of supplyr The conductortz' passes through the limit control56'to acontact fiitassociated with the arma tare 59. and" a line: 65'connects said armature to one side" of'th'e' motorifiand to one sideofthe electromagnet 2'9: The other side of the motor is" connected byfaIihe Gsto the fixed contacts 36a and oftlie switches 36 ands! respective1y: The other side of'the 'elec-tromagnet 29 is connected" bya line 61to th'e'iixed contact. 44 of the switch 31 while the main currentconductor lit'leads tothe arm lugot the' witch 3B. The oppositeendsofthe primary winding of thetr'anse i formerfil are connectedby lines,68, and 69 to the" main current" conductors 62" and Q3 respec' 1ti'velyand' thei'opposite ends of' 'the secondary winding of saidtransformer are connected ,by

linesflli' and llto one sideofthe thermostat and toon'eside ofthe'coilof'the relay 58 respectively. The other side of the'thermostat and saidarmature are connected together by a line lz.

' Ina standbyor non burning period of the ap-,

aratus, when the-thermostat 55 is notjcalling for heat, the armature5915i out of engagement with" the contact so that the circuit is open;When the circuit is open, themotor It! is deenergized'so" thatfth'e'shaft ia'ei the feed screw and'the' bloWerB are stopped. At thistime'atmo'sph'eric'pressure exists intheduct l1, and the damper 26thereinJis inthe closed position. At this time atmospheric pressuregispresent in the chambers, 35"of the diaphragm casings of the pressureresp onsive devi'ces 33,-an'd 3| so that the contacts Bite-36!) aredisengaged, the contacts A spring 43 is so connectedfto the ann 40 as tonormally'hold its contact 3612 secondary windings and deptln' t When thefuel bed has burned down to a predetermined depth, its resistance to thepassage of air therethrough is reduced, so that the pressure, of the airinithe, entireqduc't 9- is likewis e reduced. When a predeterniinedlower pressure isreached in the duct under the conditions above noted,.the contact 3617 is disengageddrom; the contactitdso that the circfiitto the motor l l, 2,325,055, u and 4a "a e disengaged {while the contats a u p and are engaged, t l it When the thermostat ll calls tor -heat,the coilof the relay "becomes energizedf'anddt attracts its armature 59toengage the same with the con =tact 64. This closes a circuit 1mmthefiline' 62 contact 64, armature as, through the '1inefii5'to one sidethe motor 10, outthe-other sideof the motori bymeans of line to contacts38a and 45. As the contact 41 is engaged'with thecon-T tact ltlcurrehtpasses through the switch ar n l8; connector ilto switch arm lllto line6 3. The i metor is'nowienergized[anddrivesthe shaft l9 l go -the feedscrew, to feed fuel to the bed on the i The motor alsddrives theblowerIto provide air underpress'ure to support combustion'l' -At thistini'efthe damper is closed so f that only a minimum amountof'air canpass the same to provide a relatively low-burningirate ior H thei'uelbed anti which rate islower than the ,fe'edihgcraterof fueltofthje} fuel bedlu a closed, the U pressure of the air in theduettbetween thedanip f erand blower builds "up and-isexerted through ithe tubesa wca e the-diaphragm3lot=device As the darnper at'thisftlmefis'still 30, at some predetermined pressure, in the-easing oi. thepressureiesponsive device 30, to function through" itsstem 42 to operatethrough the arm dB-to engage; the contact 3 36 5 with the contact 1,880. This closes asecond part0! the circuit for 3612-486 and arm lll to,the line 63. 1

* -Thelswitches 36 and :1 are so setthat at a pie; determined pressurein the windboi'r and' in the duct 9 between the ,windbox and damper,said pressure functions through the diaphragm 34; in

the-cas ng of the pressure responsive devicejl contact in engagementwithsconta'ct 2 n v this arm llj swings downwardly and disengages thecontacts 46-: and reengages thecontact- H with i the contact- 45; This:flnishes one burning oy'cle since when 'the contacts 465- are diserigaged, the circuit to the electromagnet'flbpens and thesame isdeener'gize'd: perinittingthe damperagain to"close. a i Asthecontacts fifl areatthis timeen V F gagedfthecircuit is -'again eompleted tothe-motor,lbei.'ore;iti comes tors-dead 'stop,,soi asto rea enerkize=and- 'restart'it agalnto initiate. another burning cycleas before.-Thus, the fe ed oi' fuel end, of, each burning-cycle, it' is againclosed so 1 shortly thereafter as to berestarted againbefore to causeits stem 50 to swing the arni 48 upwardly ,to' disengageits contact 41from the contact andfeng age its contact ll*wlth the cohtactj.

, 'I 'hisjcloses ahcircuit through] the lin'e65 to one side of theelectromagnetland out" theother side, and through line 61, contacts"-46, armila; connector 52 to arrnjliand thenout through the maincurrentconductor. i I

' This energizes the-electromagnet 29 which into operation at gagesi'rom the' contactitlgwhereby the circuit to thewmotor is broken andthe. motdr' 'stopsr Whemthe motor stops,-the partsreturn "to thepositionsshown in Figfil, ready to initiates'am it stops entirelyitheslowing down of the motorandi the attached blower causes a 'reduc-\tion in; pressure in the, duct to produce the recycling action byinitiating a succeeding burning "cyclebefore thernot'or stops. 1 Hence,the motor being still under momentum, sta'rtsimuch easier the beginningof each cycle of operationw I p Whenthe thermostat l5is fsatisfied-inits demand for{hea t, 'it opens-{the ,circuit to the relay I58 sojthat-the armature drops away or disenother burning'cycleas soon" as aburning period lsf'necessary to satisiythedemand' for heat'bythelthermostat. i i w 1 While in describing the invention Iw-have re--erred in detail to the-form, arrangement and constructionj'otthepartsiinvolved, the same is to i be considered only in'thelllustrati've sense and therefore I do not'wish to' be'limitedtheretoex-' cept as may be specificallyi set Iorth'in the apswings thedamperliintofitsopen horizontal it plurality ot fixedrates, one fasterthan thefeedpositionfor the passage ottheimaximum amount of air -pastthesame. 'I'he' IueIbed; having'bee'n 1 w previously built uptoaoonsiderable depthgthen starts to burn at a rate that is faster thanthe feeding rate offuel thereto and thereiorethe fuelbedburnsdownindepth. i I when the damperis opened, after a'iuelfbed.build ;up, ithepressureot the air in the entire Iclaimagmyinventionz a1., Apparatus forfisubstantially power burning solid fuel in cycleseach'having a and ern'bodying therein'a retort for supporting'a duct isthe samebut it is; still suflicient to iunction through the diaphragmin'thecasingof the a 3 device 30 to hold the contacts 360 and him theengaged position pending a reduction in iuel bed is openedand the motorreducesorslows down ducesl in pro zuqrtioi'r and this momentarily causesa pressure belo w'that at I which the diaphragm in the casing of. thedevice 3| i ls able t'o maintain fuel bedpmeansfor feeding fuel to theretort,

an air duet leading to the retort, means for inov in; air through theair duct, means forhriving said 'fuel" feeding means and said air movingv means, a damper associated with the air duct and having' relativelyheavyyandrelatively light air;

resistance positions, said driving, means being adapted to drivesaid-fuelfeeding means to feed fuel to the retort at a rate faster thanthe burriing rateof the ;fuel bed when; the'damper isin its relativelyheavy. air resistance position, means operative uponapredeterminedincrease in air 7 pressure in said duct to moveflthedamperto' a] relatively light air resistance'position whereby .1 i thefuel bed is burned at a rate fast-er than the,

feeding rate, and rneans operative when the pressurefof the fairin theair duct reaches "a 'predef termined lower pressure conditiontodeener'gize saidldriving means so thatfitslows down and so drivesj'theair moving means, asto produce a'still ,lower pressurein saidduct toreturn the damper to said, relatively heavyair resistance positionandthereby"reenergize said driving means to V 1 initiate another burningcycle.) f

c continuously :i 2; 1Apparatusr, for substantial-lye continuously powerburning: solid'fuel: in cycles, each having a-plurality?of:fixed rates,one faster than the feeding rate and another slowen thani the feedsingyrate during-"a burning; period of theap-r.

' 'paratus-and-embodying thereiira retortforsupportingw a fuelzbed,,means'; for feeding fuel to the retort, an air duct leading totheretort m'eans formovingjair throughthelairduct, a motorfor drivingsaid fuel feedinggmeans andsaid air moving meansa damperassociated: withthe airduct and-'havi-ng relatively heavy andrrelativelyzlight airresistance positions;welectrically p'operable means for moying; saiddamper from, one of-said positions the other thereof; a; circuit-forsaid [motor and said. electricallyioperablemeans; said motor beingadapted to drive said-fuel feeding means to feed'fuelto'the.retort ata-ratesfaster than; the burningrate of the-fuel bed when-said damper isin: itsrelatively heavyfair" resistance position; switch means in saidcircuit forcontrolling the" same,ja partof said switch vmeans normallyholdingithe circuit closed atone point ,tothe motorand opentosa'idelectrically'operable-means, pressure responsive meansfor actueeating saidfswitchmeans; said pressure'responsive means operatingthrough another partjoi said switch; meansupona predeterminedincrease'ofv the duct andthroughsaid switch meansfirst to open said circuit at saidsecond pointto said motor and later to said electrically operable meansand close saidcircuit to :the: motor at said first point so thatsaid-damper returns -'to its rela tively heavy air resistancepositionand 'said'mo tor is reenergized before it stops toinitiate-another burning cycle for the apparatus.

3. Apparatus for substantially continuously power; burning solid fuel incycles: eachhaving a pluralityof fixed rates; one faster than the feed-'ing rate and another slower than the feeding rate during a burningperiod of the apparatus and embodying therein a retort for supportinga-f uel bed, means for-feeding fuel-to the retort, an air duct leadingto the retort, meansfor'movingair through the air duct, a motor fordriving: said fuel feeding means and said airmoving means, a damperassociated with the air duct and having relatively heavy'andrelativelylight air resistance 'positions,,electrically operable means for movingsaid-damper from one of said positions toithe other thereof;a-circuitfor said-motor and saidelectrically operable means, said motorbeing adaptedto drive said fuel'feeding means to feed fuel to the retortata rate faster than the burning rate of the fuel bedwhen said damperis-in itsrelatively heavy air resistanceposition,

a switch insaidcircuit for controlling only the operation of said motor,a second switch in said circuit for controlling jointly the operation ofsaid motor andsaid electrically operable means, pressure responsivemeans-for actuating the first mentioned switchand operatively connectedto:

said duct at one side, of the damper, a second pressure responsive meansforpactuating said second mentioned switchand operatively con-- tomaintain the same energized, said, second men- 2,32 new I I V V n'ectedto the duct nQtheother side of th'edam-per and normally actingthrouglritsswitch'to hold saidcircuit closed-to the motor "and; openedto said electrieally operable means at a lower pres sure ofair in saidjd iet so thattheidamper nor-,

mally remains in said relatively heavy air re sistance position, saidfirst .mentioned pressure responsive means operating through its switch,

upon'a predeterminedzincrease-of air pressure in said duct to close saidcircuit to said motor tionedv pressure responsive means operatingthrough its switch at saidincrease in pressureto open thecircuit to themotor andgtov close the;

sametc saidlelectrical ly operable means so that it causes said damperto move,tosaidrelatively light'air resistance position whereby said fuelswitch to open the circuit to saidelectricallyoperable mean sothat thedamper returns to its substantially heavy air; resistance position andtoreclose; said circuit-i0 said motor before it stops and" therebytol'initiate anotherqburning cyclefor-the a aratus,v 4. In. afuellburning apparatus having burning periods; each. constituting aplurality of successively occurring burning cycles,';the-comoination ofareto1jt, means for feeding fuel to the retort to form afuel-bed-thereon;meansfor supplying air under pressureto the; fuel bed to supportcombustiontliereof,ineansfor driving said fuel feeding, means and saidair supplying means, means operative in a burning period'of theapparatus for controllingthe volume of air supplied to the fuel-bed,means-for initiating a burning cycle for theapparatus andembodying-therein means for connectingsaid driving means at one point;to said-fuel feeding: means and said air supplying means for driving thesame and: for causing said controlling means toreduoe the pressure andthe volume of the air supplied to the fuel bed a so that fuelisfed-tothe retort-faster than the supplying means at another point andfor disconnecting'said driving means from said fuel feeding means= andfrom said air supplying meansat-the first-mentioned pointand for causingsaid air controlling means to provide a max- 5. In a fuelburning:apparatushaving burning periods, eachconstituting a plurality ofsuccessively occurring burning cycles, the combination of a retort,m'eanslfor feeding fuel to the retort to'forrn a fuel bedthereon','a1neans forsupplying.

air under pressure to the fuel bed to support combustion thereoiamotorfor driving said fuel feeding means, and 'said air; supplying meansg'aheenre su ei nd the v lu e a e airvsupplied H to, thefuel -,be,d so thatfuel iisied to the-retort. faster than the burning rate thereof andwhereby, Q the fuel ,bed, builds up linedjepthe and increases its sisiant t e pa e i e1 h m h i 1 in e e th Pre ure er of and me s ov r- 3e a e:tn t c o ioft he n ea e re s r 2 thesu ii s ne e iaa eid i cui r S i mt: ano he Pa t and u f r i Sa cir ui 1?, he t e i' edi m n or ca s nsaid air controllingmeans to provide amaxi mum ,vo lume of air underpressure tothe fuel bed so' itslburning rateis faster than its feeding ia e e a her y sa f el b u s down in :dent ami ec ase s r s s n to 'eirupnned-1 v 1% thatw ch i i iate a su e d n n e c e at Pr u e w e sldeqeas for; the apparatus duringlahurningperiod.

, i r recu r n h r ias le -the com ieei ai lei-fi a m means rme nzg nlqther to? ,to,form a fuel bed thereomineansf for supb yr 1 1e r. u irPr SuIewith uelbedb up rt i combustion thereof, 1 means for; I driving:said fuel l a n ns a a r ip l in a e t electrically operated means forcontrolling f the Me a Q f u p edsto t e l a P 9 for said electricallyroperated means, means operf ative in alhurning' period of theapparatusfor i g initiating a burning eyes for the apparatus and embodyingtherein means for connecting] said flaming {means at .onefpoint tdsal'idlfuel feeding and said air. supplying means for driving the same"andforso changing the condition of circuit as to cause said,controlling, means to reduce the pressure.andftheyolume 0f the .t airsuppliedto thefuel bedso that-fuelfis'fedx the'retort faster tl'i'an theburning rate there [of and whereby the fuelfbedhuilds up depthandlincr'eases "its resistance to thepassage of air therethroughtoincrease the pressure there? =ir it f r said ma h meen ia eo wl ns thr v'alum f 1 a r i u dim s id fu be n a 1 er tive in a ch rn n Pe f t ap ra u ifqrflin t atins a n cy le fo he parat s an embad s 1 therein earmi n t e i :dr u ne int o l i m r 9! dr insfisaidg t ueltfe d ns m ansas l e t p l nsi m an i and for; causing said controlling means to reducel d 'Qitheap a s or, tia ab in y e ite the an ara sy em o the e nimeansr rorc s n z ircui at n poi o i rnotorgso thatjit drives saidfueijeeding-means and said air supplyingmeans andjonso changing; thecondition oi said circuit as to cause said controlling rneans to reducethe pressure and the }volume of I the air Sup lied to ,the, fuel bed; sgthat said u l is e 0513 et rtx t h nt burning rate of thefuel lbedthereon ,and where- ,by the fuel bed builds upin depth and "increasesits resistance? to the passage of air. therethrough g toim r e e p tereo ea eansl 'e .ative under the action o'fnthe'increased pressure t nii nfi si srth p rcui catfi i a t m nimaid m er; andaz pa sth cirjcuitat the first mentionedpoint andforagain changing the :cond'ition, ofsaid circuitfwith 1 re- *1 i e t m th i l c r c l Re eate ns, s

t t itope a es t r v e a maximumv um 9 a r m e rp e sii e tame e b dzso;t ht 1 gburning rate is faster than its feeding rate of fi In, a fuelburning apparatus having burning ,Zperiolis, each constitu-ting aplurality ,of 511C08 fuel tithe fuehbedand wherebvsaid tiu el hed b ownin depth d decre se i msis'tan i to thetainsupplied sothatgthel-pressurethereof offand'means operative underthe action of thatincreased pressureof the supplied air for operatively connecting saiddriving means to said fuel feeding means and to'said air supplying meansat another point and fordisconnecting said driv-' ing meansfor said fuelfeeding means and said 1 air supplyingjmeans at the first mentionedpoint andlfor changing the condition of said circuit soas to cause saidair controlling means to pro- ,vide a maximum volume of airunderpressure to the fuel bed so that its burning rate is faster thanits feeding rate and whereby said-fuel bed, burns down in depth anddecreases its'r'esistance to the air-supplied so that the DIBSSHIBIthereof is decreased to that whichinitiates a succeeding v b minsper df1 8. Ina fuel burning drivingsaidafuel feeding means and said blower, a;duot gfor conveying air from the blower to the jr etortQmeansinsaidductl and operable to con: V trol the ivol u me of 'yair;passingtherethrough to at 33W" @Q I ffl t M dibY t e. low essur of theair intheduct on onepside of saidcon- I H q i m an a i n v n eb i ins va ie Pt ewa p sa qrin t ng a bur i cycle -:9 e apparetusa o nec n sa d dr meat on "point tas isL l' f e e me ns "e d eid lqwer a r driving theeamezw i .saf 99 1"?! ae in ,amsi q nw di s rthe P sa e oi-airthroush td st tax the retort and whereby theair in theduct on the;

gburm'ng cycle for the, apparatusduring a burning 1 period.

t '7. In a fuel burning apparatushaving burning periods, eachconstituting ,aplurality of successively occurring burning cycles, thecombination, ofatretort, means for feeding fuelto the retort .toj'form afuel bed thereon, means f orsupply ing airlunder Jpressuretothe fuelbedto support combustion thereof, amotor for drivingsaid fuel feedingmeans and said air supplying means, a

" e a e t tha hi h nitiates-a succeedi Y eu a e s id a ing burningcycle; for

is lume. 1 a r fi der; P e su m ns o other'sidefof the control means,builds up to a relatively high pressure, and means actuated by saidhighpressure of air in the duct for connect- ,ing said drivingimeans atanother point to said fuel feeding means andto said blower while lowerpressure air in the duct ontheotherjside of said control: means, throughsaid means actuated therebydisconnects said driving means; I therefromat the first mentioned point and operates said control meanstopermit-the maxi -mum' passagetof air throughi the duct to pro"- videaburning rate for the fuelbed that is faster than the feeding rate forthe fuelthereto in the final partof said burning cycle-so that the}pressure isjreducedfthroughout .thedirct; said twolast mentioned meansoperating'atsaid re; duced pressure to initiate a succeedin'g burningcycle of the apparatus; i

9. In a fuel burning apparatus Ingj a V Iume oftair under pressure,amotor for ap ar t isy in periods, each constituting a plurality ofsuccesit i i l q eiu' insr ar ins yc e th com inatio of a retort, meansfor feeding fuel-,to 'theretort f m a e b dt r aera ihleweri r odu I ghaving burning i periods, each constituting a. plurality of succesisively occurring burning cycles; the combination} f of a retort,,meansfor feeding fuel to ytheretort j to form a fuel bedthereoma blower forproduc.-

